Editing Single Post. Single.PHP not working..

I’m trying to change the layout of the single post once it’s clicked through… At the moment a list of all other posts appear underneath… Which is no good.

I’ve tried making changes in Single.php but nothing is happening. The code there doesn’t effect anything at all… when I delete all the content… The site is not affected so there is no connection there.

Is there anywhere else I can edit?

Cheers

Sam